“…Thus, various memristor emulators, either constructed from off-the-shelf components, [9,10,11,12,13,14,15] or from generalized memristors based on circuits with special topologies, [9,14,15,16,17] make greater contributions to modeling, to analyzing, especially to realizing memristor-based chaotic circuits by replacing nonlinear resistance elements in classic chaotic circuits and in this way many novel features of chaotic behaviors could be observed. [18,19,20,21] In more details, several nonlinearities are used to describe the relation between magnetic flux and electric charge of these memristors, such as HP memristor model, [22,23] non-smooth piecewise linearity, [10,25] smooth cubic nonlinearity [12,18,19,26] and smooth piecewise-quadratic nonlinearity. [18,25] Generation of memristor emulators were complicated and not convenient to circuit analysis.…”